MUSCLES. 



35 



man, the progress of science only increases his admiration. 

 What would it be if life, that force of which he is conscious, 

 and which he shares with all organized beings, should cease 

 to be to him an impenetrable secret! 



Muscles. United by the joints, the bones of the skeleton, 

 taken as a whole, approach the form of the body. But in 

 order to put these bones in motion, 

 and to bring these joints into play, 

 we must call to our aid an external 

 force. By itself, if we may be per- 

 mitted a very familiar comparison, 

 the skeleton is a puppet of which 

 the different parts are put in motion 

 by threads. The threads by which 

 the skeleton is moved are the 

 muscles. The name muscles is 

 given to the masses of red tissue 

 which constitute the flesh. We 

 have already described the ele- 

 ments of the muscular tissue; how 

 the primitive microscopic bundles, 

 united into secondary ones', become 

 muscular or fleshy fibres easily dis- 

 tinguished by the naked eye. These 

 fibres are parallel or divergent ac- 

 cording to the muscle, and assume 

 different forms. Sometimes it is 

 that of a ribbon (sartorius, sterno- 

 hyoid, &c.); sometimes a broad 

 web-like tissue of a texture more or 

 less firm, like the transverse muscles 

 of the abdomen; in one region the 

 muscle, swollen in the centre, and 

 drawn out like a thread at the ends, 

 resembles a spindle in form (biceps, 

 straight muscle of the thigh); in another it is fan-shaped 

 (temporal, obturator), or like a ring (orbicular muscle of 

 the lips and eyes) ; or the fibres converge like the radii of a 

 circle (the diaphragm); or are disposed in parallel lines like 



Fig. 13. Biceps muscle of the 

 arm. 



A. Body of the muscle. 

 B. B. Superior tendons. 

 C. Inferior tendons. 



